matlab拟合出错：Function value and YDATA sizes are not equal.

来源：学生作业帮编辑：作业帮分类：综合作业时间：2024/07/07 16:56:23

matlab拟合出错：Function value and YDATA sizes are not equal.
x=1:1:5;
y=[1976882 2972166 3752790 4077716 4154964]';
function y=fitline_1(a,x)
y=a(1)+a(2)*x+a(3)*x.^2+a(4)*x.^3;
a=lsqcurvefit('fitline_1',[1;1;1;1],x,y);
请问哪里出现了问题?

把y赋值语句的转置符号去掉即可.x是行向量,y应该也是行向量才对. 另外,使用多项式拟合完全可以用polyfit函数,比这个简单很多：x=1:1:5;
y=[1976882 2972166 3752790 4077716 4154964];
a=polyfit(x,y,3);
plot(x,y,'ro',x,polyval(a,x),'.-')

再问：能帮忙直接写一下拟合完成的公式吗？其实我只想要一个公式
再答：拟合公式：y = p1*x^3 + p2*x^2 + p3*x + p4
其中系数：
p1 = -2751.5
p2 = -1.3893e+05
p3 = 1.4634e+06
p4 = 6.4873e+05

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